Dear Terry, Luke, and all, As you know, Australia is an extremely dry continent. This means that Australian farmers have always been pre-occupied with rainfall and its measurement.
Prior to metrication we divided each inch of rain into 100 points, and rainfall figures were given in these points. I suspect that the word points came from the decimal points of rain that fell on a particular farm � 'We didn't get an inch of rain, we only got 23 (decimal) points.' After metrication, farmers soon realised that a millimetre of rain was equivalent to a litre of water on a square metre. For the first time ever, Australian farmers could actually carry out farm water calculations. For example, if you want to calculate the size of a water storage tank that you can attach to the side of your new 5 metre by 10 metre storage shed, you figure as follows: My new shed is 5 x 10 = 50 m^2 My average rainfall is 550 mm each year (That's here in Geelong) The most my tanks need to hold (each year) is 50 x 550 = 27�500 litres = 27.5�kilolitres. I will leave to others the equivalent calculation in old units. The starting points are: Average rainfall 21 inches and 650 points Shed size: 16 feet 4 27/32 inches by 32 feet 9 11/16 inches Please provide the tanks capacity in gallons (imp. or U.S. as required) Needless to say irrigation calculations are equivalently simple with metric units and equivalently difficult with old units. For example, if you want to water 20 hectares of land with the equivalent of 15 millimetres of rainfall you proceed as follows: 20 hectares = 20 x 10�000 m^2 = 200�000 m^2 Rainfall equivalent required = 15 mm Amount of water required = 200�000 x 15 = 3�000�000 litres = 3000 kilolitres = 3 megalitres Again I leave the equivalent calculation to others using acres and inches. The starting points are: Area = 50 acres (approx) Rainfall equivalent required = 590 points = 19/32 inches (approx) Please provide the result of your calculation in gallons (imp. or U.S. as required) and acre-feet. I believe that one of the reasons that leading Australian farmers adopted metric units so rapidly was because of the ease of these and similar calculations. The use of metric units made these rainfall and water calculations possible, for farmers, for the first time � ever � probably since Babylonian farmers first faced the same problems some 10�000 years ago. Cheers, Pat Naughtin CAMS Geelong, Australia on 2002-09-10 02.06, Terry Simpson at [EMAIL PROTECTED] wrote: > I thought that I had sent this reply to the list but I had mistakenly > sent it directly to the author. Sorry for the error. > > Here is what I said... > > > > Although one expression uses SI units, the other doesn't. > >> It amounts to the same thing then. >> >> From: Luc English [mailto:[EMAIL PROTECTED]] >> Sent: vendredi 6 septembre 2002 10:10 >> To: [EMAIL PROTECTED] >> Subject: [ukma] rainfall >> >> >> Note that L/m2 of rainfall is the same as mm of rainfall. > > #>- Subscription Options; -<# > #>- http://list.to/srv/SubOpt?id=_s%2FkZWRdAq7Z%2Fh9loIHXgZkWf%2FLd990tF%3F%3D > -<# > > UK Metrication Association > http://www.metric.org.uk > Messages posted on the list should not be reproduced without permission. > Mailinglist WWW Archive; > http://list.to/srv/WebArchive?id=_y%2BMuWw%2BgZOn1ZWUJ6zhcYw%3D >
